This invention relates generally to ventilating apparatus and in particular to dampers for regulating gas flow through a duct.
Adjustable dampers are commonly used in air distribution systems to balance airflow through ducts near the supply air discharge outlets. Occasionally, such dampers are also used to balance return air at or near the return air inlets.
Air ducts are manufactured in a variety of shapes, such as square, round and rectangular, and it is a common practice to provide a diffuser, or other form of air apparatus, at the supply air discharge outlets and the return air inlets. Dampers can be sized and shaped to fit the shape of either the duct or the inlet of a particular air apparatus. If necessary, adapters can be used to provide a transition between one duct shape and another.
When a damper is mounted on or near a diffuser, best overall performance is obtained when the damper provides an adjustable air restriction without adversely affecting the distribution pattern of the diffuser. Known round damper designs, such as opposed blade, butterfly, radial and shutter, succeed, with varying degrees of difficulty and effectiveness, in providing such desired performance. Those round damper designs which provide the desired performance with a minimum of complexity and cost are to be preferred.
In view of the foregoing, it is a general object of the present invention to provide a new and improved opposed blade balanced damper.
It is a more specific object of the present invention to provide an opposed blade balanced damper wherein the balanced damper provides an adjustable air restriction without adversely affecting the distribution pattern of a diffuser or other air apparatus.
It is a still more specific object of the present invention to provide an opposed blade balanced damper which can be easily and economically manufactured without sacrificing performance.